Since we are dicussing MixedSound, I have a proposal, currently
implemented in muO, for a better panning, by using a -4.5 dB pan law as
explained here:
http://www.cs.cmu.edu/~music/icm-online/readings/panlaws/index.htmlSo I propose in MixedSound
add: aSound pan: leftRightPan volume: volume
"Add the given sound with the given left-right pan, where 0.0 is full
left, 1.0 is full right, and 0.5 is centered. The loudness of the sound
will be scaled by volume, which ranges from 0 to 1.0."
| vol |
vol := (volume max: 0.0) min: 1.0.
sounds := sounds copyWith: aSound.
(self class panValuesFor: leftRightPan) allIn: [:leftPan :rightPan |
leftVols := leftVols copyWith: (leftPan * vol) rounded.
rightVols := rightVols copyWith: (rightPan * vol) rounded]
where, on the class side, we have
panValuesFor: aPos
"aPos ranges from 0.0 to 1.0 (Squeak convention)"
^ (MusicMachine db45PanAt: (aPos * 2) - 1) collect: [:ea |
((ea * ScaleFactor) rounded max: 0) min: ScaleFactor]
The MusicMachine class is in muO, so it would have to be refactored
here. The code is
db45PanAt: pNumber
"pNumber ranges from -1 (45 degrees left) to 1 (45 degrees right)"
"Uses -4.5 dB pan law
ref:
http://www.cs.cmu.edu/~music/icm-online/readings/panlaws/index.html"
| theta |
theta := (pNumber + 1) * Float pi / 4.
^ {
"left" (theta cos * (Float halfPi - theta) / Float halfPi) sqrt.
"right" (theta sin * theta / Float halfPi) sqrt
}
Stef
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